#!/usr/bin/env python
# -*- coding: utf-8 -*-

import sys


class MyError(Exception):
    def __str__(self):
        return "I'm a self-defined Error!"


def main():
    try:
        print("**********Start of main()************")
        if len(sys.argv) == 1:
            raise MyError()
        print("**********End of main()************")
    except MyError as e:
        print(e)


if __name__ == '__main__':
    main()
